Convert indicated odometer miles into real distance after a tire diameter change. See actual miles, percent error, and the diameter ratio — free, private.
Enter values to see results
100% browser-based
Runs locally in this tab
No upload required
Your files never leave this device
Nothing is stored
Close the tab and the input is gone
Instant results
No queue and no server wait
Enter stock size, new size, and the miles on the trip odo or the cluster. The same overall-diameter ratio used for speedometer error converts indicated distance into ground distance. A taller tire under-reports miles; a shorter tire over-reports them on the same trip.
You see actual miles, error percent, the mile gap, and the diameter ratio in one view. That is what you need for a service-interval sanity check or a mileage-warranty conversation after a size change — not a legal odometer disclosure form.
Default indicated distance is 1000 miles so you can scale a road trip or an oil-change interval. The tool does not rewrite the ECU or the instrument cluster; it tells you what the numbers would have been at the new diameter.
No VIN and no upload. Stock size, new size, and indicated miles stay in the tab. Close the page and they are gone. For instantaneous speed at 60 mph, use Speedometer Error with the same two sizes. Nothing is stored on a server.
Use the size the odometer was calibrated for, typically the OE placard size.
Metric or flotation. Diameter ratio is computed from those two codes.
Trip odo, interval miles, or a round number such as 1000. The result scales linearly with that input.
Actual distance, the mile difference, and the diameter ratio appear together. Nothing is written back to the vehicle.
Straight answers on privacy, limits, and how the workspace behaves.
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